Tuesday

Solar flares are efficient particle accelerators and prime laboratories for studying astrophysical acceleration and transport. Our understanding of electron acceleration and transport in flares has been enhanced by observationally-driven kinetic modelling and multi-wavelength observations from X-rays to (E)UV to radio. However, many questions remain about how and where energetic electrons are accelerated, and how different plasma environments (e.g., collisions, turbulence) affect their transport and observed properties. In this talk, I will review recent advances and discuss the importance of determining the accelerated electron pitch-angle distribution (or directivity), an unknown property in most flares but a vital diagnostic of the acceleration mechanism. In late 2021, the first X-ray stereoscopic observations in decades with Solar Orbiter/STIX and new X-ray missions at Earth should help to constrain this important property. Moreover, I will briefly discuss how properties of the flare acceleration region can be further constrained by combining remote and in-situ observations of flare energetic electrons at the Sun and in the heliosphere, aided by new Solar Orbiter and Parker Solar Probe data and state-of-the-art transport modelling in these different plasma environments.